// The MIT License (MIT)
//
// Copyright (c) Itay Grudev 2015 - 2020
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

//
//  W A R N I N G !!!
//  -----------------
//
// This file is not part of the SingleApplication API. It is used purely as an
// implementation detail. This header file may change from version to
// version without notice, or may even be removed.
//
#pragma once

#include <QtCore/QSharedMemory>
#include <QtNetwork/QLocalServer>
#include <QtNetwork/QLocalSocket>
#include "singleapplication.h"

struct InstancesInfo {
	bool primary;
	quint32 secondary;
	qint64 primaryPid;
	char primaryUser[128];
	quint16 checksum; // Must be the last field
};

struct ConnectionInfo {
	qint64 msgLen = 0;
	quint32 instanceId = 0;
	quint8 stage = 0;
};

class SingleApplicationPrivate : public QObject {
	Q_OBJECT
public:
	enum ConnectionType : quint8 {
		InvalidConnection = 0,
		NewInstance = 1,
		SecondaryInstance = 2,
		Reconnect = 3
	};
	enum ConnectionStage : quint8 {
		StageHeader = 0,
		StageBody = 1,
		StageConnected = 2,
	};
	Q_DECLARE_PUBLIC(SingleApplication)

		SingleApplicationPrivate(SingleApplication *q_ptr);
	~SingleApplicationPrivate() override;

	static QString getUsername();
	void genBlockServerName();
	void initializeMemoryBlock() const;
	void startPrimary();
	void startSecondary();
	bool connectToPrimary(int msecs, ConnectionType connectionType);
	quint16 blockChecksum() const;
	qint64 primaryPid() const;
	QString primaryUser() const;
	void readInitMessageHeader(QLocalSocket *socket);
	void readInitMessageBody(QLocalSocket *socket);
	static void randomSleep();

	SingleApplication *q_ptr;
	QSharedMemory *memory;
	QLocalSocket *socket;
	QLocalServer *server;
	quint32 instanceNumber;
	QString blockServerName;
	SingleApplication::Options options;
	QMap<QLocalSocket*, ConnectionInfo> connectionMap;

public Q_SLOTS:
	void slotConnectionEstablished();
	void slotDataAvailable(QLocalSocket*, quint32);
	void slotClientConnectionClosed(QLocalSocket*, quint32);
};

